Electrically-heated boiler.



c. AALBO RG.

ELECTRIGALLY HEATED BOILER.

APPLICATION FILED JULY 8, 1909. v v 974,330. Patented Nov. 1, 1910.

2 SEEET8-SHEET 1.

iii Lyn v Z 'K a a i 14 i 1E f. *fi L LI"? 7F") J P f 9 6% "J H f f ""W1 L -U f 9 k "J I m 1 I 1 L'\- T JJ J 9 M WITNESSES: Z INVENTOE ATTORNEY G. AALBORG. ELBGYTRIGALLY HEATED BOILER.

APPLICATION FILED JULY 8, 1909.

atented Nov. 1,1910.

'2 SHEETS-SHEET 2.

lllllllll I I I I fr:

WITNESSES:

Z Z INXENTOR ATTORNEY UNITED STATES PATENT OFFICE.

CHRISTIAN AALBORG, 0F WILKINSlZURG, PENNSYLVANIA, ASSIGNOR T0 VJESTING-HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENN-SYLVANIA.

ELECTRICALLY-HEATED BOILER.

Specification of Letters Yatent.

Patented Nov. 1, 1910.

To all whom it may concern:

Be it known that I, CHRISTIAN AALBoRG, a citizen of the United States,and a resident of Vilkinsburg, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement inElecti'ically-l-leated Boilers, of which the following is aspecification.

My invention relates to electrically heated boilers or steam gene ators.and it has for its object to provide a device of this character thatshall be simple and durable in construction and that shall provide amaximum heating surfacr with a minimum external radiating suriace.

Figure 1 of the accompanying drawings is an elevation of a boilerconstructed in accordance with my invention and having a plurality ofunits arranged in multiple, Fig. 2 a view partially in section andpartially in elevation of one-of the units shown in Fig. 1, Fig. 3 is anelevation at right angles to that of Fig. 2, and Fig. l is a detail viewof a portion of the resistance elementwhich is embodied in the appa'atusshown in the other figures.

Referring to the drawings, the structure here shown comprises a tank orboiler 1 in which water, or some other fluid to be heated, is-containedand a plurality of like heater units 2, 3 and .l which are connected tothe tank 1 in multiple arrangement.

Each of the units is composed of a body member, preferably constructedof cast metal, havin two similar halves 5' and 6 which are cliimpedtogether by any. suitable means, such as bolts 7, the joint between thetwo halves being carefully fitted and provided with a suitable packing8.

Each of the units is provided with an inlet pipe 9 and an outlet pipe10, so that a continuous circulation of liquid may be cll'ected from thetank through the unit and back into the tank. Each of the castings 5 and(l is provided with a plurality otin-,

wardly extending projections 11 in which relatively narrow slots 12 arecut from the outer surlace of the unit so that its surfaces becomedeeply corrugated but the probroken by the narrow slots 12 in which theresistance units 13 of the device are disposed;

As shown in Fig. 4 of the drawings, each resistance unit comprises astrip or ribbon of steel, or other suitable conducting material, havinga plurality of slots 14 cut alternately from opposite edges to provide azigzag path for the electric current. The slots 12 are first providedwith insulating cells 15 of U-shapedsection and then the resistanceribbon is forced into place between the layers of insulation and iswound back and forth through successive'slots, it being carried beyondthe ends of the castings in order to avoid grounding thereon. (See Figs.2 and It. is evident that a very large proportion or ribbon istransmitted directly through the adjacent Walls of the castings to theliquid within, while the external radiation is reduced to a minimum byreason of the form of the casting. If sufiicient heat is imparted to theliquid within the unit to materially increase its pressure, thisincreased pressure will tend to force the walls of the device even morefirmly into contact with the insulated resistance element. Theelectrical connections between groups of resistance may be arranged inany suitable manner, accord ing to the heat required, and the voltage ofthe circuit from which energy is received.

I desire that variations in size and arrangement of parts, which do notdepart from the spirit of my invention, shall be included Within itsscope.

I claim as my invention:

1. An electrically heated steam generator comprising a. relatively flatresistance element, a receptacle having a plurality of ribs orprojections on the inner surfaces of its Walls, and slots cut in itsouter wall and extending into the projections or ribs to receive saidresistance element, whereby the fluid pressure Within the receptaclecompresses the resistance element.

2. An electrically heated steam generator comprising a cast metalreceptacle having inlet and outlet ports at opposite ends, and aplurality of pa 'allel ribs projecting inwardly from its walls andparallel slot-s cut into the ribs or projections from its outer surface,and a resistance strip or ribbon of the heat generated in the resistancestrip threaded back and forth through the slots 1 pressure in thereceptacle eompressesthe re- 10 for transmitting heat through the projecsistance element.

tions into the liquid contained within the re- In testimony whereof, Ihave hereunto ceptacle, whereby the fluid pressure Within subscribed myname this 28th day of June,

compresses the resistance strip or ribbon. 1909.

3. A heating receptacle for liquids having CHRISTIAN AALBORG. inwardlyro ecting ribs provided with re- Witnesses: cesses, and an insulatedresistance element R. J. DEARBORN, seated in said recesses, whereby thefluid B. B. HINES.

